Interlocking peel-away dilation catheter

ABSTRACT

A dilatation balloon catheter which is capable of being removed from a patient while leaving a guide wire in place has a longitudinal slit extending from its proximal end to a position near its inflatable balloon. The catheter has an inflation lumen for applying fluid to inflate the balloon, and an insertion lumen through which the guide wire passes. The slit communicates with the insertion lumen so that the catheter can be peeled off of the guide wire as the catheter is withdrawn from the patient and the guide wire remains in place in the patient.

This is a continuation of application Ser. No. 166,976 filed on Mar. 10,1988, abandoned as of the date of this application.

BACKGROUND OF THE INVENTION

1. Field of the Invention.

The present invention relates to the field of angioplasty. Inparticular, the present invention relates to dilatation ballooncatheters which are insertable into a patient over a guide wire.

2. Description of the Prior Art.

Angioplasty has gained wide acceptance in recent years as an efficientand effective method for treating certain types of vascular diseases. Inparticular, angioplasty is widely used for opening of stenosis in thecoronary arteries, although it is also used for treatment of stenoses inother parts of the vascular system.

The most widely used form of angioplasty makes use of a balloon catheterwhich has an inflatable balloon at its distal end. Using fluoroscopy,the physician guides the catheter through the vascular system until theballoon is positioned across the stenosis. The balloon is then inflatedby supplying fluid under pressure through an inflation lumen to theballoon. The inflation of the balloon causes stretching of the arteryand pressing of the lesion into the artery wall to reestablishacceptable blood flow through the artery.

Guide wires are often used for establishing the path to the stenoses sothat the balloon catheter can subsequently be positioned. The guide wirenormally is advanced through the stenosis, and commonly is left in placeduring the inflation of the balloon.

Balloon catheters used for angioplasty are available in differentballoon diameters. There are instances in which it becomes necessary toexchange one size of balloon catheter for another during an angioplastyprocedure. When this happens, it is very advantageous to leave the guidewire in place while the first balloon catheter is removed. This allowsthe second balloon catheter to be reinserted without having to firstreestablish the path by inserting a new guide wire.

In the past, however, the removal of the balloon catheter withoutremoving the guide wire has been complicated because the ballooncatheter is inserted over the guide wire. To remove the ballooncatheter, while leaving the guide wire in place, there must be a portionof the guide wire extending out of the balloon catheter at the proximalend so that the guide wire can be gripped and held in place as theballoon catheter is removed.

One solution is to remove the initial guide wire while leaving thecatheter in place and then inserting an "exchange wire" in its place.The exchange wire is long enough so that the portion of its lengthextending outside of the patient is longer than the length of thecatheter. This allows a portion of the exchange wire to be available forgripping at all times regardless of the position of the catheter. Thereare, however, several problems with this approach. The use of anexchange wire essentially doubles the normal length of the guide wire,which makes the exchange wire difficult to handle and manipulate. Thisextra length is normally of no use to the physician during angioplasty,since exchanging catheters is required only in a fraction of the totalnumber of angioplasty procedures. The extra steps of exchanging theguide wire for an exchange wire and the increased difficulty of handlinga wire of much greater length have been required in the past in order toexchange balloon catheters. A more convenient and easier to use systemwould be desirable.

SUMMARY OF THE INVENTION

The present invention is a balloon catheter which can be removed from apatient over a standard length guide wire (typically about 150 cm)without removing the guide wire from the patient. The catheter of thepresent invention includes means for opening a longitudinal slit whichcommunicates with the insertion lumen through which the guide wirepasses. The slit extends from near the proximal end of the catheter to aposition near the inflatable balloon, so that the length of the catheterwhich does not contain a slit is shorter than the length of guide wirenormally located outside of the patient and extending beyond theproximal end of the catheter.

To remove the catheter from the patient, the guide wire is held in placewhile the catheter is removed from the patient. The guide wire exits thecatheter through the slit, so that as the catheter is withdrawn from thepatient, the distance between the exit of the guide wire from thecatheter and the distal end of the catheter becomes progressivelyshorter. In other words, the catheter tube is "peeled away" from theguide wire as the catheter is withdrawn from the patient. When thecatheter has reached a position in which the distal end of the catheteris outside of the patient and the guide wire can be grasped beyond thedistal end of the catheter, the remainder of the catheter can be pulledoff of the proximal end of the guide wire.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of the peel-away dilatation balloon catheterof the present invention, with the balloon shown in an inflatedcondition.

FIG. 2 is a sectional view along section 2--2 of FIG. 1 showing the duallumen catheter tube of the peel-away catheter of FIG. 1.

FIGS. 3A and 3B show sectional views of the proximal end portion of thepeel-away dilatation catheter of FIG. 1 illustrating movement of thecatheter tube with respect to the stripper hub as the catheter iswithdrawn from the patient while the guide wire stays in place.

FIGS. 4A and 4B are sectional views illustrating a method of forming analternate construction of the dual lumen catheter tube.

FIGS. 5A and 5B, 6A and 6B, 7A and 7B and 8A and 8B are sectional viewsillustrating other embodiments of the dual lumen catheter tube withresealable slits.

FIG. 9 is a sectional view of the proximal end of another embodiment ofthe peel-away catheter of the present invention.

FIG. 10 is a sectional view of the distal end of still anotherembodiment of the peel-away catheter.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Peel-away dilatation balloon catheter 10 of the present invention shownin FIG. 1 includes a dual lumen catheter tube 12 which has an inflationlumen 14 and a through lumen or insertion lumen 16. Mounted at distalend 18 of tube 12 is inflatable balloon 20. Inflation lumen 14 opensinto the interior of balloon 20. Also shown within the interior ofballoon 20 is a mid-balloon radiopaque marker 22, which is useful foridentifying the location of balloon 20 by fluoroscopy.

In a preferred embodiment of the present invention, tube 12 is anextruded dual lumen tube made from polyethylene. Balloon 20 is formedfrom a polymer material such as polyolefin, and is bonded to tube 12 atthe proximal and distal ends of balloon 20 by a suitable adhesive, suchas an epoxy.

At proximal end 24 of catheter tube 12, inflation port 26 is connectedthrough strain relief sleeve 28 to inflation lumen 14. Inflation port 26is preferably a luer fitting which is attached to an inflation device(not shown).

As shown in FIGS. 1 and 2, tube 12 has a longitudinally extendingopening or slit 30 which communicates with insertion lumen 16. Slit 30extends from proximal end 24 of tube 12 to end point 32, which islocated near the proximal portion of inflation balloon 20. The slit 30is resiliently closed under normal conditions, however, it may beforcibly opened. In a preferred embodiment, the distance D betweendistal tip 34 of catheter 10 and end point 32 of slit 30 isapproximately ten inches. This distance D is selected to be less than anormal length of catheter guide wire which extends outside beyond theproximal end of the catheter during an angioplasty procedure.

In FIG. 1, peel-away catheter 10 is shown in place on guide wire 36,which may be of any conventional design (including a "dilating guidewire" which has a small diameter balloon at its distal end). The distalend of guide wire 36 extends out through distal tip 34 of catheter 10.Guide wire 36 extends all the way through insertion lumen 16 and outinsertion lumen hub 38 at the proximal end 24 of catheter 10. .Iadd.Asillustrated in FIG. 1, the guide wire 36 is laterally displaced from theproximal end 24 of the catheter 10. .Iaddend.Insertion lumen hub 38includes a first tubular section 40 which is generally axially alignedwith catheter tube 12 and is positioned within insertion lumen 16. Hub38 also has a second tubular portion 42 which extends at an angleoutward through slit 30. The outer end of tubular section 42 carries aluer fitting 44. Insertion lumen hub 38 is carried by and is movablewith stripper hub 46.

Stripper hub 46 is a generally cylindrical sleeve having a pair of ribs48 for gripping and having a side port 50 through which tube section 42of insertion lumen hub 38 extends. Stripper hub 46 is slidable in anaxial direction along the length of catheter tube 12 between theposition shown in FIG. 1 and a position which is limited by the endpoint 32 of slit 30. Stop collar 52 is attached to the proximal end ofcatheter tube 12 to stop the proximal motion of stripper hub 46 andprevent it from being removed off the proximal end of catheter tube 12.

Catheter 10 of the present invention has the advantage of being able tobe removed from the patient while leaving guide wire 36 in place. FIGS.3A and 3B, together with FIG. 1, illustrate the "peel-away" removal ofcatheter 10 over guide wire 36. .Iadd.As illustrated in FIGS. 3A and 3B,the guide wire 36 is laterally displaced from the catheter tube 12..Iaddend.

In FIG. 3A, the withdrawal of catheter 10 from the patient has begun. Bycomparing FIG. 3A with FIG. 1, it can be seen that stripper hub 46 is nolonger adjacent proximal end 24 of tube 12. This is accomplished by thephysician by holding stripper hub 46 in place, while applying force tothe proximal end of cathether 10 so that relative movement of cathetertube 12 with respect to stripper hub 46 is taking place. FIG. 3B showscatheter 10 at a position where end point 32 has reached stripper hub46. At this point distal tip 34 is either outside of the guide catheter(not shown) or can be pulled outside the guide catheter by proximalmovement of catheter 10, so that it is possible for the physician tograsp a portion of guide wire 36 distally of tip 34. The remainingdistance D of catheter 10 can be pulled off of the guide wire 36 withoutdisturbing guide wire 36, because it is possible to grasp guide wire 36at a position between distal tip 34 and the guide catheter.

Once catheter 10 has been removed from guide wire 36, a differentdilatation catheter of either the same, or different construction can bethreaded over guide 36 and into the patient. Through the entireprocedure, the distal end of guide wire 36 has remained in place withinthe patient. This is advantageous because it avoids the time required toreinsert the guide wire; it avoids the cost of an exchange wire and thehandling problems associated with an exchange wire; and it reduces thedanger involved in recrossing a freshly crossed lesion.

FIGS. 4A and 4B illustrate an alternative embodiment of the presentinvention. As shown in FIG. 4A, catheter tube 60 is a dual lumen tubehaving an inflation lumen 62 and a through lumen or insertion lumen 64.Slit 66 extends through the wall of tube 60 in an area of reduced wallthickness to divide the outer wall of tube 60 into two flaps 68 and 70.

As shown in FIG. 4B, tube 60 is then compressed or heat formed so thatflap 70 overlaps flap 68 (or vice versa). This overlapping providesgreater structural strength for tube 60, while still allowing flaps 68and 70 to be parted as there is relative movement between stripper hub46 and tube 60.

FIGS. 5A and 5B, 6A and 6B, 7A and 7B, and 8A and 8B illustrate otherembodiments which feature extruded dual lumen tubing with resealableslits. The advantages of a resealable slit are that no blood leakageoccurs, and that the through lumen can also be used for blood pressuremeasurement and distal dye delivery.

In FIGS. 5A and 5B, catheter tube 80 is a dual lumen tube having aninflation lumen 82 and a through lumen 84. Slit 86 (which is open inFIG. 5A and closed in FIG. 5B) divides the outer wall of tube 80 intoflaps 88 and 90. C-shaped hooks 92 and 94 at the edges flaps 88 and 90respectively, run longitudinally the length of slit 86, and engage oneanother to seal slit 86 as shown in FIG. 5B. The seal provided by hooks92 and 94 can be broken to open slit 86 by relative movement of stripperhub 46.

The embodiments shown in FIGS. 6A and 6B, 7A and 7B, and 8A and 8B aregenerally similar to FIGS. 5A and 5B (and similar reference numerals areused). In FIGS. 6A and 6B, ramp hooks 96 and 98 replace C-shaped hooks92 and 94. In FIGS. 7A and 7B, barbs 100 and 102 replace hooks 92 and94. In FIGS. 8A and 8B, ball 104 and socket 106 replace hooks 92 and 94.

FIG. 9 shows the distal portion of another embodiment of the peel-awaycatheter which is generally similar to the embodiment of FIGS. 1-3, andsimilar reference characters are used. The embodiment of FIG. 9 includeknife blade 110 which is carried by stripper hub 46. Relative movementof stripper hub 46 toward the distal end of catheter 10 cause knifeblade 110 to cut a slit in tubing 12 (which was extruded without aslit). The advantage of this embodiment is that until the time ofslitting no blood leakage can occur and blood pressure measurements anddistal dye delivery can be accomplished by using through lumen 16.

FIG. 10 shows the distal portion of still another embodiment of thepeel-away catheter. In this embodiment, dual lumen tubing 120 can takeany one of several forms, including the forms shown and discussedpreviously. Tubing 120 has an inflation lumen 122 and a through lumen124. At its distal end, tubing 120 has a reduced diameter bonding region126 to which balloon waist 128 is bonded. Through lumen 124 extendsdistally slightly beyond inflation lumen 122 and has an extension innerlumen 130 connected at its distal end. Connected to balloon waist 128 isinflatable balloon segment 132 (shown inflated). Balloon waist 128,inflatable balloon segment 132 and distal bond segment 134 may be aone-piece (integral) construction or may be formed of differentmaterials. Distal bond segment 134 is bonded to the distal end of innerlumen 130.

In FIG. 10, the longitudinal slit in tubing 120 extends to point 136,which is near bonding region 126. The distance from point 136 to thedistal tip of the catheter is approximately ten inches.

In conclusion, the peel-away catheter of the present invention providesa simple yet very effective way of performing an angioplasty dilatationcatheter exchange without having to remove the guide wire from thepatient. With the present invention, it is not necessary to provide aguide wire of excessive length for those occasions where a catheterexchange is required, and yet the physician can make an exchange quicklyand simply in those cases where it becomes apparent that catheterexchange is necessary.

Another important advantage of the present invention is that it providesmaximum pushability through the patient because the guide wire 36supports catheter 10 along its entire length.

During insertion of a catheter 10 of this design, the tripper hub 46 maybe located at the proximal end 24 of slit 30 and insertion made by atraditional threading onto guide wire 36.

Alternatively, stripper hub 46 and insertion hub 38 may be located nearthe patient. In this arrangement, the catheter tubing 12 is pushedthrough the stripper hub 46, resiliently closes over the guide wire 36and enters the patient.

Although the present invention has been described with reference topreferred embodiments, workers skilled in the art will recognize thatchanges may be made in form and detail without departing from the spiritand scope of the invention.

What is claimed is:
 1. A catheter which is insertable and removable overa guide wire which has one end adapted for insertion into a vessel of apatient and an opposite end which extends outside of the patient, thecatheter comprising:a tubular member having a proximal end, a distalend, a first lumen for transmitting fluid, and a second lumen throughwhich the guide wire passes; an inflatable balloon carried by thetubular member adjacent the distal end and in communication with thefirst lumen; wherein the tubular member includes a longitudinal openingthrough a side wall of the tubular member and connected to the secondlumen, the longitudinal opening extending from adjacent the proximal endof the tubular member to a position spaced from a proximal end of theinflatable balloon and dividing the side wall into first and second wallportions on opposite sides of the longitudinal opening, with thelongitudinal opening permitting movement of the guide wire through thelongitudinal opening as the tubular member is removed from the patientwhile the guide wire remains in the patient; interlocking means carriedadjacent longitudinal free edge portions of the first and second wallportions, and including first interlocking means carried at alongitudinal free edge of the first wall portion and second interlockingmeans carried at a longitudinal free edge of the second wall portion,the first and second interlocking means being selectively interlockableto close the longitudinal opening; and a generally cylindrical sleevemember slidably mounted about the tubular member, the sleeve memberhaving a tubular section through which the guide wire extends and whichdisengages the interlocking means and locally spreads apart thelongitudinal opening to permit passage of the tubular section and guidewire therethrough.
 2. The catheter of claim 1 wherein the interlockingmeans includes a pair of cooperable resilient flaps which resilientlycloses the longitudinal opening to prevent passage of the guide wiretherethrough with a first flap extending along the longitudinal freeedge portion of the first wall portion and overlapping a second flapextending along the longitudinal free edge portion of the second wallportion.
 3. The catheter of claim 2 wherein the flaps have thinner wallsections adjacent the longitudinal opening and thicker wall sectionsaway from the opening.
 4. The catheter of claim 1 wherein the tubularsection of the sleeve member includes an insertion hub having:a firsttubular portion generally axially aligned with the tubular member andpositioned within the second lumen; a second tubular portion extendingat an angle from the first tubular section outward through thelongitudinal opening; and wherein the guide wire passes through thefirst and second portions of the insertion hub.
 5. The catheter of claim4 wherein the second tubular portion of the insertion hub includes aluer fitting through which the guide wire passes.
 6. The catheter ofclaim 4 wherein the sleeve member includes:a side port therethrough forthe second tubular portion; and wherein the sleeve member is slidable onthe tubular member of the catheter over a span of the longitudinalopening.
 7. The catheter of claim 1 wherein the sleeve member includesat least one exterior rib which extends circumferentially about thesleeve member for facilitating gripping of the sleeve member.
 8. Thecatheter of claim 1 wherein the tubular member includes a stop collaradjacent the proximal end for limiting the motion of the sleeve memberin a proximal direction.
 9. The catheter of claim 1 wherein a distancefrom the position spaced from the proximal end of the inflatable balloonto the distal tip of the catheter is approximately ten inches.
 10. Thecatheter of claim 1 wherein the first and second interlocking meansfurther comprise:a first C-shaped hook and a second C-shaped hook, thefirst C-shaped hook extending along the longitudinal free edge of thefirst wall portion and being cooperable with the second C-shaped hookextending along the longitudinal free edge of the second wall portion.11. The catheter of claim 1 wherein the first and second interlockingmeans further comprise:a first ramp-shaped hook and a second ramp-shapedhook, the first hook extending along the longitudinal free edge of thefirst wall portion and being cooperable with the second hook extendingalong the longitudinal free edge of the second wall portion.
 12. Thecatheter of claim 1 wherein the first and second interlocking meansfurther comprise:a first barb-shaped hook and a second barb-shaped hook,the first hook extending along the longitudinal free edge of the firstwall portion and being cooperable with the second hook extending alongthe longitudinal free edge of the second wall portion.
 13. The catheterof claim 1 wherein the first and second interlocking means furthercomprise:a rib portion and a groove portion, the rib portion extendingalong the longitudinal free edge of the first wall portion and beingcooperable with the groove portion extending along the longitudinal freeedge of the second wall portion.
 14. A method of removing a ballooncatheter from a patient while leaving a guide wire in place with aproximal end of the guide wire outside the patient and a distal end ofthe guide wire within the patient, the method comprising:providing agenerally cylindrical stripper hub about a proximal end of the ballooncatheter which extends outside of the patient; applying force to theballoon catheter at its proximal end in a direction which causes theballoon catheter to be withdrawn proximally through the stripper hub andout of the patient; maintaining the guide wire in an essentiallystationary position, by grasping the stripper hub and maintaining thestripper hub in an essentially stationary position relative to thepatient to cause a longitudinal slit in a side wall of the ballooncatheter to open by separating interlocked interlocking means carried onopposing wall portions of the side wall defining the slit, as theballoon catheter passes proximally through the stationary stripper huband to permit the guide wire to pass generally laterally out through thelongitudinal slit in the side wall of the balloon catheter until aremaining length of the catheter positioned over the guide wire isshorter than a length of the guide wire extending outside the patient;and removing the remaining length of balloon catheter proximally off ofthe guide wire.
 15. The method of claim 14 wherein the applying forcestep and the maintaining the guide wire position step are performedsimultaneously.
 16. The method of claim 14 and furthercomprising:grasping a portion of the guide wire located distally of adistal tip of the balloon catheter when that portion of the ballooncatheter becomes exposed outside of the patient.
 17. The method of claim16 wherein the grasping step and the removing step are performedessentially simultaneously.
 18. A method of exchanging a firstangioplasty dilation catheter in a patient with a second angioplastydilation catheter while leaving a guide wire in place with a proximalend of the guide wire outside the patient and a distal end of the guidewire within the patient, the method comprising:providing a generallycylindrical stripper hub about a proximal end of the first angioplastydilation catheter which extends outside of the patient; applying forceto the first catheter at its proximal end in a direction which causesthe first catheter to be withdrawn proximally through the stripper huband out of the patient; maintaining the guide wire in an essentiallystationary position, by grasping the stripper hub and maintaining thestripper hub in an essentially stationary position relative to thepatient to cause a longitudinal slit in a side wall of the firstcatheter to open by separating interlocked interlocking means carried onopposing wall portions of the side wall defining the slit as the firstballoon catheter passes proximally through the stationary stripper huband to permit the guide wire to pass laterally out through thelongitudinal slit in the side wall of the first catheter and through aside port in the stripper hub until a remaining length of the firstcatheter positioned over the guide wire is shorter than length of theguide wire extending outside the patient; removing a remaining length ofthe first catheter proximally off of the guide wire; threading thesecond angioplasty dilation catheter onto the proximal end of the guidewire; and inserting the second angioplasty dilation catheter into thepatient and over the guide wire within the patient.
 19. A catheter whichis insertable and removable over a guide wire, the cathetercomprising:an inflatable balloon; a shaft supporting the balloon at adistal end thereof, and having an inflation port at a proximal endthereof, the shaft having an inflation lumen extending from theinflation port to an interior of the balloon and a guide wire lumenextending through the interior of the balloon, with the guide wire lumencomprising means for releasably holding a guide wire adjacent to theinflation lumen along substantially an entire length of the shaft andsaid guide wire lumen including interlocking parting means forpermitting the shaft and the guide wire to be peeled away from oneanother along substantially the entire length of the shaft; and agenerally cylindrical sleeve member mounted about the shaft which iscapable of relative longitudinal movement with respect to the shaft forcausing the parting means to unlock and be parted, thereby permittingthe shaft and guide wire to be peeled apart. .Iadd.
 20. A ballooncatheter, comprising:a. an elongate shaft having a proximal end, adistal end, an exterior and a guide wire lumen extending therethrough,the distal end of the shaft including an inner tube disposed in an outertube, the elongate shaft also having a longitudinal slit extendingdistally from the proximal end of the shaft to provide access to theguidewire lumen from the exterior of the shaft, wherein the slit isdefined between adjacent flaps when the slit is open, and wherein theflaps provide structural strength to the shaft when the slit is closed;b. an inflatable balloon having a proximal end and a distal end, theproximal end of the balloon connected to the distal end of the shaft; c.a guide wire having a proximal end and a distal end, the distal endbeing disposed in the guide wire lumen and the proximal end beinglaterally displaced from the elongate shaft; and d. a sliding memberdisposed on the elongate shaft and extending at least partially into thelongitudinal slit, the sliding member engaging the guide wire disposedin the guide wire lumen. .Iaddend..Iadd.21. A balloon catheter as inclaim 20, wherein a distal end of the inner tube is connected to thedistal end of the balloon and a distal end of the outer tube isconnected to the proximal end of the balloon. .Iaddend..Iadd.22. Aballoon catheter as in claim 21, wherein the inner tube is about 10inches long. .Iaddend..Iadd.23. A balloon catheter, comprising: a. aproximal shaft having a proximal end, a distal end, an exterior and aproximal guide wire lumen extending therethrough, the proximal shaftalso having a longitudinal slit to provide access to the proximal guidewire lumen from the exterior of the shaft, wherein the slit is definedbetween adjacent flaps when the slit is open and wherein the flapsprovide structural strength to the proximal shaft when the slit isclosed; b. an outer tube having a proximal end and a distal end, theproximal end of the outer tube connected to the distal end of theproximal shaft; c. an inner tube having a proximal end, a distal end anda distal guide wire lumen extending therethrough, the inner tubedisposed in the outer tube to define an annular lumen therebetween; andd. a balloon having a proximal end and a distal end, the proximal end ofthe balloon connected to the distal end of the outer tube, the distalend of the balloon connected to the distal end of the inner tube..Iaddend..Iadd.24. A balloon catheter as in claim 23, furthercomprising: e. a sliding member disposed on the proximal shaft andextending at least partially into the longitudinal slit..Iaddend..Iadd.25. A balloon catheter as in claim 24, further includinga guide wire disposed in the proximal guide wire lumen, wherein thesliding member engages the guide wire. .Iaddend..Iadd.26. A ballooncatheter as in claim 25, wherein the inner tube is about 10 inches long..Iaddend..Iadd.27. A balloon catheter, comprising:a. a first shafthaving a proximal end, a distal end, a first inflation lumen extendingtherethrough, and a first guide wire lumen extending therethrough, thefirst shaft also having a slit extending therealong to provide access tothe first guide wire lumen, wherein the slit is defined between adjacentflaps when the slit is open, and wherein the flaps provide structuralstrength to the first shaft when the slit is closed; b. a second shafthaving a proximal end, a distal end, a second inflation lumen extendingtherethrough, and a second guide wire lumen extending therethrough, theproximal end of the second shaft connected to the distal end of thefirst shaft, the second shaft having a length of about 10 inches; and c.a balloon connected to the distal end of the second shaft..Iaddend..Iadd.28. A balloon catheter as in claim 27, wherein the slitterminates at the distal end of the first shaft. .Iaddend..Iadd.29. Aballoon catheter as in claim 27, further comprising: d. a sliding memberdisposed in the slit. .Iaddend..Iadd.30. A balloon catheter as in claim29, further including a guide wire disposed in the proximal guide wirelumen, wherein the sliding member engages the guide wire..Iaddend..Iadd.31. A balloon catheter as in claim 30, wherein the slitterminates at the distal end of the first shaft. .Iaddend..Iadd.32. Aballoon catheter, comprising:a. an elongate shaft having a proximal end,a distal end, an exterior, a guide wire lumen, an inflation lumen, and alongitudinally-extending lateral opening which provides access to theguide wire lumen from the exterior of the shaft, wherein the lateralopening is defined between adjacent flaps when the lateral opening isopen, and wherein the flaps provide structural strength to the shaftwhen the lateral opening is closed; b. an inflatable balloon connectedto the distal end of the elongate shaft, the inflatable balloon being influid communication with the inflation lumen; c. a guide wire disposedin the guide wire lumen; and d. a sleeve member slidably disposed on theshaft, the sleeve member including a portion which penetrates thelateral opening into the guide wire lumen and at least partiallysurrounds the guide wire disposed in the guide wire lumen, the portionof the shaft proximal of the sleeve member remaining substantiallycoaxially aligned with the portion of the shaft distal of the sleevemember. .Iaddend..Iadd.33. A balloon catheter as in claim 32, whereinthe longitudinally extending lateral opening extends to a point about 10inches proximal of the balloon. .Iaddend..Iadd.34. A balloon catheter asin claim 32, wherein the distal end of the elongate shaft includes aninner tube disposed in an outer tube. .Iaddend..Iadd. A balloon catheteras in claim 34, wherein a distal end of the inner tube is connected to adistal end of the balloon and a distal end of the outer tube isconnected to a proximal end of the balloon. .Iaddend..Iadd.36. A ballooncatheter as in claim 35, wherein the inner tube is about 10 inches long..Iaddend.